Electrolux RF Capacitor Replacement

[AviatorAddis]

Does anyone know the value of the RF suppression capacitor used on an Electrolux 30 XXX motor? I have the paper type (missing a good portion of it's wax) that I want to replace with a new capacitor before the old one shorts out with a fireworks display. Also, where does the grounding lead attach as most caps only have two leads. If any of you have removed them, do you notice any RF interference running the vac? Thanks.

 

[davetranter]

Suppressor capacitor

If you can't find an 'original' type component, a 0.05 uF capacitor rated at about 600V DC /200V AC should suffice, assuming you are on 110V mains (Polypropylene types are best for this duty). Running the motor without the cap will accelerate brush and commutator burning, as well as generating RF interference. Since these components are non-polarised, it won't matter which 'way round' it's wired. If the old component is a three-wire device, connect two in 'series' and 'ground' the midpoint.

Hope that makes sense, if not reply again for clarification...

All best

Dave T

 

[AviatorAddis]

That makes sense. I tie two of them together, and the connection between the two grounds to the chassis. The only thing, looking at digikey, I can't find one that matches your specs.

http://www.digikey.com/us/en/mkt/capacitors.html

I live in Southern California. Figured the house mains were 120v. Would these caps be the same for any vacuum motor? I have no idea how they affect brush wearing. Does it keep the arc across them from alternating? I really appreciate the help, my local vacuum shop had no idea.

 

[davetranter]

Digikey, Etc.

Just had a look at your 'link'. Look under 'film types' Voltage: 600DC/200AC...
Capacitance: .047/.05 uF... Material: Polypropylene or Polyester.

0.047 is a far more 'common' type than 0.05, which will probably make them cheaper.(that's just how it is ) The difference is insignificant in this application.

I found two types as good examples Part No. 338-3455-ND or PVC6147-ND.

You may be able to pick a couple up locally from any radio/TV repair shop, just tell them it's for 'electric motor suppression duty', they should have something suitable.

Unfortunately Paper types are now only available in very large types, for fluorescent lighting and motors, so you won't get an exact (authentic) match. The new cap(s) should be smaller, though, so you MAY be able to 'hollow out' the old component and 'hide' the new one inside, to preserve the appearance of your machine. If you do this, be sure to insulate it all very well...

You were right about my description of 'how to connect'..

All best

Dave T

P.S. A bit about brush arcing...
As the commutator turns, and the brush leaves the edge of each segment, a high voltage is generated (in exactly the same way as an auto ignition coil). The cap absorbs this energy and releases it into the next segment as it moves under the brush. Without the cap the arcing is much stronger, and soon burns the edges of the segments and brushes.